An abstract base class for slider widgets. More...

#include <qwt_abstract_slider.h>

Inheritance diagram for QwtAbstractSlider:

Collaboration diagram for QwtAbstractSlider:

Classes
class	PrivateData
Public Types
enum	ScrollMode { ScrNone, ScrMouse, ScrTimer, ScrDirect, ScrPage }
Public Slots
virtual void	setValue (double val)
	Move the slider to a specified value.
virtual void	fitValue (double val)
	Set the slider's value to the nearest integer multiple of the step size.
virtual void	incValue (int steps)
	Increment the value by a specified number of steps.
virtual void	setReadOnly (bool)
Signals
void	valueChanged (double value)
	Notify a change of value.
void	sliderPressed ()
void	sliderReleased ()
void	sliderMoved (double value)
Public Member Functions
	QwtAbstractSlider (Qt::Orientation, QWidget *parent=NULL)
	Constructor.
virtual	~QwtAbstractSlider ()
	Destructor.
void	setUpdateTime (int t)
	Specify the update interval for automatic scrolling.
void	stopMoving ()
	Stop updating if automatic scrolling is active.
void	setTracking (bool enable)
	Enables or disables tracking.
virtual void	setMass (double val)
	Set the slider's mass for flywheel effect.
virtual double	mass () const
virtual void	setOrientation (Orientation o)
Orientation	orientation () const
bool	isReadOnly () const
bool	isValid () const
void	setValid (bool valid)
Protected Member Functions
virtual void	setPosition (const QPoint &)
virtual void	valueChange ()
virtual void	timerEvent (QTimerEvent *e)
virtual void	mousePressEvent (QMouseEvent *e)
virtual void	mouseReleaseEvent (QMouseEvent *e)
virtual void	mouseMoveEvent (QMouseEvent *e)
virtual void	keyPressEvent (QKeyEvent *e)
virtual void	wheelEvent (QWheelEvent *e)
virtual double	getValue (const QPoint &p)=0
	Determine the value corresponding to a specified poind.
virtual void	getScrollMode (const QPoint &p, int &scrollMode, int &direction)=0
	Determine what to do when the user presses a mouse button.
void	setMouseOffset (double)
double	mouseOffset () const
int	scrollMode () const
Properties
bool	readOnly
bool	valid
double	mass
Orientation	orientation

Detailed Description

An abstract base class for slider widgets.

QwtAbstractSlider is a base class for slider widgets. It handles mouse events and updates the slider's value accordingly. Derived classes only have to implement the getValue() and getScrollMode() members, and should react to a valueChange(), which normally requires repainting.

Definition at line 28 of file qwt_abstract_slider.h.

Member Enumeration Documentation

enum QwtAbstractSlider::ScrollMode

Scroll mode

See also:: getScrollMode()

Enumerator:

ScrNone
ScrMouse
ScrTimer
ScrDirect
ScrPage

Definition at line 37 of file qwt_abstract_slider.h.

Constructor & Destructor Documentation

QwtAbstractSlider::QwtAbstractSlider	(	Qt::Orientation	orientation,
		QWidget *	parent = `NULL`
	)		`[explicit]`

Constructor.

Parameters:

orientation	Orientation
parent	Parent widget

Definition at line 54 of file qwt_abstract_slider.cpp.

References orientation(), and QwtAbstractSlider::PrivateData::orientation.

                                                   : 
    QWidget(parent, NULL)
{
    d_data = new QwtAbstractSlider::PrivateData;
    d_data->orientation = orientation;

#if QT_VERSION >= 0x040000
    using namespace Qt;
#endif
    setFocusPolicy(TabFocus);
}

QwtAbstractSlider::~QwtAbstractSlider ( ) [virtual]

Destructor.

Definition at line 68 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::tmrID.

{
    if(d_data->tmrID) 
        killTimer(d_data->tmrID);

    delete d_data;
}

Member Function Documentation

void QwtAbstractSlider::fitValue ( double value ) [virtual, slot]

Set the slider's value to the nearest integer multiple of the step size.

Parameters:

value Value

See also:: setValue(), incValue()

Reimplemented from QwtDoubleRange.

Definition at line 556 of file qwt_abstract_slider.cpp.

References ScrMouse, QwtAbstractSlider::PrivateData::scrollMode, and stopMoving().

Referenced by mouseReleaseEvent(), setPosition(), and timerEvent().

{
    if (d_data->scrollMode == ScrMouse) 
        stopMoving();
    QwtDoubleRange::fitValue(value);
}

virtual void QwtAbstractSlider::getScrollMode	(	const QPoint &	p,
		int &	scrollMode,
		int &	direction
	)		`[protected, pure virtual]`

Determine what to do when the user presses a mouse button.

This function is abstract and has to be implemented by derived classes. It is called on a mousePress event. The derived class can determine what should happen next in dependence of the position where the mouse was pressed by returning scrolling mode and direction. QwtAbstractSlider knows the following modes:

QwtAbstractSlider::ScrNone: Scrolling switched off. Don't change the value.
QwtAbstractSlider::ScrMouse: Change the value while the user keeps the button pressed and moves the mouse.
QwtAbstractSlider::ScrTimer: Automatic scrolling. Increment the value in the specified direction as long as the user keeps the button pressed.
QwtAbstractSlider::ScrPage: Automatic scrolling. Same as ScrTimer, but increment by page size.

Parameters:

p	point where the mouse was pressed

Return values:

scrollMode	The scrolling mode
direction	direction: 1, 0, or -1.

Implemented in QwtDial, QwtSlider, and QwtWheel.

Referenced by mousePressEvent(), and wheelEvent().

virtual double QwtAbstractSlider::getValue ( const QPoint & p ) [protected, pure virtual]

Determine the value corresponding to a specified poind.

This is an abstract virtual function which is called when the user presses or releases a mouse button or moves the mouse. It has to be implemented by the derived class.

Parameters:

p point

Implemented in QwtDial, QwtSlider, and QwtWheel.

Referenced by mousePressEvent(), and setPosition().

void QwtAbstractSlider::incValue ( int steps ) [virtual, slot]

Increment the value by a specified number of steps.

Parameters:

steps number of steps

See also:: setValue()

Reimplemented from QwtDoubleRange.

Definition at line 568 of file qwt_abstract_slider.cpp.

References ScrMouse, QwtAbstractSlider::PrivateData::scrollMode, and stopMoving().

Referenced by QwtDial::keyPressEvent(), and keyPressEvent().

{
    if (d_data->scrollMode == ScrMouse) 
        stopMoving();
    QwtDoubleRange::incValue(steps);
}

bool QwtAbstractSlider::isReadOnly ( ) const

In read only mode the slider can't be controlled by mouse or keyboard.

Returns:: true if read only

See also:: setReadOnly()

Definition at line 98 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::readOnly.

Referenced by QwtDial::drawFocusIndicator(), QwtDial::keyPressEvent(), QwtCompass::keyPressEvent(), keyPressEvent(), mouseMoveEvent(), mousePressEvent(), mouseReleaseEvent(), and wheelEvent().

{
    return d_data->readOnly;
}

bool QwtAbstractSlider::isValid ( ) const [inline]

See also:: QwtDblRange::isValid()

Reimplemented from QwtDoubleRange.

Definition at line 74 of file qwt_abstract_slider.h.

Referenced by QwtDial::drawContents(), QwtKnob::drawKnob(), QwtAnalogClock::drawNeedle(), QwtCompass::drawScaleContents(), QwtSlider::drawSlider(), QwtDial::keyPressEvent(), keyPressEvent(), mouseMoveEvent(), mousePressEvent(), mouseReleaseEvent(), and wheelEvent().

void QwtAbstractSlider::keyPressEvent ( QKeyEvent * e ) [protected, virtual]

Handles key events

Key_Down, KeyLeft
Decrement by 1
Key_Up, Key_Right
Increment by 1

Parameters:

e Key event

See also:: isReadOnly()

Reimplemented in QwtCompass, and QwtDial.

Definition at line 377 of file qwt_abstract_slider.cpp.

References incValue(), isReadOnly(), isValid(), mitk::Key_Down, mitk::Key_Left, mitk::Key_Right, mitk::Key_Up, orientation(), QwtDoubleRange::prevValue(), sliderMoved(), and QwtDoubleRange::value().

{
    if ( isReadOnly() )
    {
        e->ignore();
        return;
    }

    if ( !isValid() )
        return;

    int increment = 0;
    switch ( e->key() ) 
    {
        case Qt::Key_Down:
            if ( orientation() == Qt::Vertical )
                increment = -1;
            break;
        case Qt::Key_Up:
            if ( orientation() == Qt::Vertical )
                increment = 1;
            break;
        case Qt::Key_Left:
            if ( orientation() == Qt::Horizontal )
                increment = -1;
            break;
        case Qt::Key_Right:
            if ( orientation() == Qt::Horizontal )
                increment = 1;
            break;
        default:;
            e->ignore();
    }

    if ( increment != 0 )
    {
        QwtDoubleRange::incValue(increment);
        if (value() != prevValue())
            emit sliderMoved(value());
    }
}

virtual double QwtAbstractSlider::mass ( ) const [virtual]

Reimplemented in QwtWheel.

void QwtAbstractSlider::mouseMoveEvent ( QMouseEvent * e ) [protected, virtual]

Mouse Move Event handler

Parameters:

e	Mouse event

Definition at line 311 of file qwt_abstract_slider.cpp.

References QwtDoubleRange::exactPrevValue(), QwtDoubleRange::exactValue(), isReadOnly(), isValid(), QwtAbstractSlider::PrivateData::mass, QwtDoubleRange::prevValue(), ScrMouse, QwtAbstractSlider::PrivateData::scrollMode, setPosition(), sliderMoved(), QwtAbstractSlider::PrivateData::speed, QwtAbstractSlider::PrivateData::time, and QwtDoubleRange::value().

{
    if ( isReadOnly() )
    {
        e->ignore();
        return;
    }

    if ( !isValid() )
        return;

    if (d_data->scrollMode == ScrMouse )
    {
        setPosition(e->pos());
        if (d_data->mass > 0.0) 
        {
            double ms = double(d_data->time.elapsed());
            if (ms < 1.0) 
                ms = 1.0;
            d_data->speed = (exactValue() - exactPrevValue()) / ms;
            d_data->time.start();
        }
        if (value() != prevValue())
            emit sliderMoved(value());
    }
}

double QwtAbstractSlider::mouseOffset ( ) const [protected]

Definition at line 580 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::mouseOffset.

Referenced by QwtDial::getValue().

{
    return d_data->mouseOffset;
}

void QwtAbstractSlider::mousePressEvent ( QMouseEvent * e ) [protected, virtual]

Mouse press event handler

Parameters:

e	Mouse event

Definition at line 150 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::direction, getScrollMode(), getValue(), isReadOnly(), isValid(), QwtAbstractSlider::PrivateData::mouseOffset, qwtMax, ScrMouse, QwtAbstractSlider::PrivateData::scrollMode, ScrPage, ScrTimer, sliderPressed(), QwtAbstractSlider::PrivateData::speed, stopMoving(), QwtAbstractSlider::PrivateData::time, QwtAbstractSlider::PrivateData::timerTick, QwtAbstractSlider::PrivateData::tmrID, QwtAbstractSlider::PrivateData::updTime, and QwtDoubleRange::value().

{
    if ( isReadOnly() )
    {
        e->ignore();
        return;
    }
    if ( !isValid() )
        return;

    const QPoint &p = e->pos();

    d_data->timerTick = 0;

    getScrollMode(p, d_data->scrollMode, d_data->direction);
    stopMoving();
    
    switch(d_data->scrollMode)
    {
        case ScrPage:
        case ScrTimer:
            d_data->mouseOffset = 0;
            d_data->tmrID = startTimer(qwtMax(250, 2 * d_data->updTime));
            break;
        
        case ScrMouse:
            d_data->time.start();
            d_data->speed = 0;
            d_data->mouseOffset = getValue(p) - value();
            emit sliderPressed();
            break;
        
        default:
            d_data->mouseOffset = 0;
            d_data->direction = 0;
            break;
    }
}

void QwtAbstractSlider::mouseReleaseEvent ( QMouseEvent * e ) [protected, virtual]

Mouse Release Event handler

Parameters:

e	Mouse event

Definition at line 202 of file qwt_abstract_slider.cpp.

{
    if ( isReadOnly() )
    {
        e->ignore();
        return;
    }
    if ( !isValid() )
        return;

    const double inc = step();
    
    switch(d_data->scrollMode) 
    {
        case ScrMouse:
        {
            setPosition(e->pos());
            d_data->direction = 0;
            d_data->mouseOffset = 0;
            if (d_data->mass > 0.0) 
            {
                const int ms = d_data->time.elapsed();
                if ((fabs(d_data->speed) >  0.0) && (ms < 50))
                    d_data->tmrID = startTimer(d_data->updTime);
            }
            else
            {
                d_data->scrollMode = ScrNone;
                buttonReleased();
            }
            emit sliderReleased();
            
            break;
        }

        case ScrDirect:
        {
            setPosition(e->pos());
            d_data->direction = 0;
            d_data->mouseOffset = 0;
            d_data->scrollMode = ScrNone;
            buttonReleased();
            break;
        }

        case ScrPage:
        {
            stopMoving();
            if (!d_data->timerTick)
                QwtDoubleRange::incPages(d_data->direction);
            d_data->timerTick = 0;
            buttonReleased();
            d_data->scrollMode = ScrNone;
            break;
        }

        case ScrTimer:
        {
            stopMoving();
            if (!d_data->timerTick)
                QwtDoubleRange::fitValue(value() + double(d_data->direction) * inc);
            d_data->timerTick = 0;
            buttonReleased();
            d_data->scrollMode = ScrNone;
            break;
        }

        default:
        {
            d_data->scrollMode = ScrNone;
            buttonReleased();
        }
    }
}

Orientation QwtAbstractSlider::orientation ( ) const

Referenced by QwtSlider::drawSlider(), QwtSlider::drawThumb(), QwtWheel::drawWheel(), QwtWheel::drawWheelBackground(), QwtSlider::getScrollMode(), QwtWheel::getValue(), QwtSlider::getValue(), keyPressEvent(), QwtSlider::layoutSlider(), QwtWheel::minimumSizeHint(), QwtSlider::minimumSizeHint(), QwtAbstractSlider(), QwtWheel::setOrientation(), and QwtSlider::setOrientation().

int QwtAbstractSlider::scrollMode ( ) const [protected]

Definition at line 585 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::scrollMode.

Referenced by QwtDial::getValue().

{
    return d_data->scrollMode;
}

void QwtAbstractSlider::setMass ( double val ) [virtual]

Set the slider's mass for flywheel effect.

If the slider's mass is greater then 0, it will continue to move after the mouse button has been released. Its speed decreases with time at a rate depending on the slider's mass. A large mass means that it will continue to move for a long time.

Derived widgets may overload this function to make it public.

Parameters:

val	New mass in kg

See also:: mass()

Reimplemented in QwtWheel.

Definition at line 513 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::mass.

{
    if (val < 0.001)
       d_data->mass = 0.0;
    else if (val > 100.0)
       d_data->mass = 100.0;
    else
       d_data->mass = val;
}

void QwtAbstractSlider::setMouseOffset ( double offset ) [protected]

Definition at line 575 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::mouseOffset.

Referenced by QwtDial::getValue().

{
    d_data->mouseOffset = offset;
}

virtual void QwtAbstractSlider::setOrientation ( Orientation o ) [virtual]

void QwtAbstractSlider::setPosition ( const QPoint & p ) [protected, virtual]

Move the slider to a specified point, adjust the value and emit signals if necessary.

Definition at line 282 of file qwt_abstract_slider.cpp.

References fitValue(), getValue(), and QwtAbstractSlider::PrivateData::mouseOffset.

Referenced by mouseMoveEvent(), and mouseReleaseEvent().

{
    QwtDoubleRange::fitValue(getValue(p) - d_data->mouseOffset);
}

void QwtAbstractSlider::setReadOnly ( bool readOnly ) [virtual, slot]

En/Disable read only mode

In read only mode the slider can't be controlled by mouse or keyboard.

Parameters:

readOnly Enables in case of true

See also:: isReadOnly()

Definition at line 85 of file qwt_abstract_slider.cpp.

References readOnly, and QwtAbstractSlider::PrivateData::readOnly.

{
    d_data->readOnly = readOnly;
    update();
}

void QwtAbstractSlider::setTracking ( bool enable )

Enables or disables tracking.

If tracking is enabled, the slider emits a valueChanged() signal whenever its value changes (the default behaviour). If tracking is disabled, the value changed() signal will only be emitted if:

the user releases the mouse button and the value has changed or
at the end of automatic scrolling.

Tracking is enabled by default.

Parameters:

enable true (enable) or false (disable) tracking.

Definition at line 302 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::tracking.

{
    d_data->tracking = enable;
}

void QwtAbstractSlider::setUpdateTime ( int t )

Specify the update interval for automatic scrolling.

Parameters:

t	update interval in milliseconds

See also:: getScrollMode()

Definition at line 138 of file qwt_abstract_slider.cpp.

References QuadProgPP::t(), and QwtAbstractSlider::PrivateData::updTime.

{
    if (t < 50) 
        t = 50;
    d_data->updTime = t;
}

void QwtAbstractSlider::setValid ( bool valid ) [inline]

Parameters:

valid true/false

See also:: QwtDblRange::isValid()

Reimplemented from QwtDoubleRange.

Definition at line 80 of file qwt_abstract_slider.h.

References QwtDoubleRange::isValid().

Referenced by QwtAnalogClock::setTime().

void QwtAbstractSlider::setValue ( double val ) [virtual, slot]

Move the slider to a specified value.

This function can be used to move the slider to a value which is not an integer multiple of the step size.

Parameters:

val new value

See also:: fitValue()

Reimplemented from QwtDoubleRange.

Definition at line 541 of file qwt_abstract_slider.cpp.

References ScrMouse, QwtAbstractSlider::PrivateData::scrollMode, and stopMoving().

Referenced by QwtDial::keyPressEvent(), QwtCompass::keyPressEvent(), and QwtAnalogClock::setTime().

{
    if (d_data->scrollMode == ScrMouse) 
        stopMoving();
    QwtDoubleRange::setValue(val);
}

void QwtAbstractSlider::sliderMoved ( double value ) [signal]

This signal is emitted when the user moves the slider with the mouse.

Parameters:

value new value

Referenced by QwtDial::keyPressEvent(), keyPressEvent(), mouseMoveEvent(), and wheelEvent().

void QwtAbstractSlider::sliderPressed ( ) [signal]

This signal is emitted when the user presses the movable part of the slider (start ScrMouse Mode).

Referenced by mousePressEvent().

void QwtAbstractSlider::sliderReleased ( ) [signal]

This signal is emitted when the user releases the movable part of the slider.

Referenced by mouseReleaseEvent().

void QwtAbstractSlider::stopMoving ( )

Stop updating if automatic scrolling is active.

Definition at line 124 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::tmrID.

Referenced by fitValue(), incValue(), mousePressEvent(), mouseReleaseEvent(), setValue(), and timerEvent().

{
    if(d_data->tmrID)
    {
        killTimer(d_data->tmrID);
        d_data->tmrID = 0;
    }
}

void QwtAbstractSlider::timerEvent ( QTimerEvent * e ) [protected, virtual]

Qt timer event

Parameters:

e	Timer event

Definition at line 423 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::direction, QwtDoubleRange::exactValue(), QuadProgPP::exp(), fitValue(), QwtDoubleRange::incPages(), QwtAbstractSlider::PrivateData::mass, ScrMouse, QwtAbstractSlider::PrivateData::scrollMode, ScrPage, ScrTimer, QwtAbstractSlider::PrivateData::speed, QwtDoubleRange::step(), stopMoving(), QwtAbstractSlider::PrivateData::timerTick, QwtAbstractSlider::PrivateData::tmrID, QwtAbstractSlider::PrivateData::updTime, and QwtDoubleRange::value().

{
    const double inc = step();

    switch (d_data->scrollMode)
    {
        case ScrMouse:
        {
            if (d_data->mass > 0.0)
            {
                d_data->speed *= exp( - double(d_data->updTime) * 0.001 / d_data->mass );
                const double newval = 
                    exactValue() + d_data->speed * double(d_data->updTime);
                QwtDoubleRange::fitValue(newval);
                // stop if d_data->speed < one step per second
                if (fabs(d_data->speed) < 0.001 * fabs(step()))
                {
                    d_data->speed = 0;
                    stopMoving();
                    buttonReleased();
                }

            }
            else
               stopMoving();
            break;
        }

        case ScrPage:
        {
            QwtDoubleRange::incPages(d_data->direction);
            if (!d_data->timerTick) 
            {
                killTimer(d_data->tmrID);
                d_data->tmrID = startTimer(d_data->updTime);
            }
            break;
        }
        case ScrTimer:
        {
            QwtDoubleRange::fitValue(value() +  double(d_data->direction) * inc);
            if (!d_data->timerTick) 
            {
                killTimer(d_data->tmrID);
                d_data->tmrID = startTimer(d_data->updTime);
            }
            break;
        }
        default:
        {
            stopMoving();
            break;
        }
    }

    d_data->timerTick = 1;
}

void QwtAbstractSlider::valueChange ( ) [protected, virtual]

Notify change of value

This function can be reimplemented by derived classes in order to keep track of changes, i.e. repaint the widget. The default implementation emits a valueChanged() signal if tracking is enabled.

Reimplemented from QwtDoubleRange.

Reimplemented in QwtDial, QwtSlider, and QwtWheel.

Definition at line 490 of file qwt_abstract_slider.cpp.

References QwtAbstractSlider::PrivateData::tracking, QwtDoubleRange::value(), and valueChanged().

{
    if (d_data->tracking)
       emit valueChanged(value());  
}

void QwtAbstractSlider::valueChanged ( double value ) [signal]

Notify a change of value.

In the default setting (tracking enabled), this signal will be emitted every time the value changes ( see setTracking() ).

Parameters:

value new value

Referenced by valueChange().

void QwtAbstractSlider::wheelEvent ( QWheelEvent * e ) [protected, virtual]

Wheel Event handler

Parameters:

e	Whell event

Definition at line 342 of file qwt_abstract_slider.cpp.

References getScrollMode(), QwtDoubleRange::incPages(), isReadOnly(), isValid(), QwtDoubleRange::prevValue(), ScrNone, sliderMoved(), QwtDoubleRange::value(), and WHEEL_DELTA.

{
    if ( isReadOnly() )
    {
        e->ignore();
        return;
    }

    if ( !isValid() )
        return;

    int mode = ScrNone, direction = 0;

    // Give derived classes a chance to say ScrNone
    getScrollMode(e->pos(), mode, direction);
    if ( mode != ScrNone )
    {
        const int inc = e->delta() / WHEEL_DELTA;
        QwtDoubleRange::incPages(inc);
        if (value() != prevValue())
            emit sliderMoved(value());
    }
}

Property Documentation

double QwtAbstractSlider::mass [read, write]

Returns:: mass

See also:: setMass()

Reimplemented in QwtWheel.

Definition at line 20 of file qwt_abstract_slider.h.

Qt::Orientation QwtAbstractSlider::orientation [read, write]

Returns:: Orientation

See also:: setOrientation()

Definition at line 24 of file qwt_abstract_slider.h.

bool QwtAbstractSlider::readOnly [read, write]

Definition at line 18 of file qwt_abstract_slider.h.

Referenced by setReadOnly().

bool QwtAbstractSlider::valid [read, write]

Definition at line 19 of file qwt_abstract_slider.h.

The documentation for this class was generated from the following files:

QwtAbstractSlider Class Reference

Classes

Public Types

Public Slots

Signals

Public Member Functions

Protected Member Functions

Properties

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Property Documentation